Filter.



PATENTED DEC. 4, 1906 @mmm;

J. MAODOUGALL- FILTER; APPLIOATION FILED 1UG.13 1900. RENEWED m. '1.1904,

M Mmm 5;

JOHN MAODOUGALL, OF DETROIT, MICHIGAN.

FILTER.

Specification of Letters Patent.

Patented Dec. 4;, 1906.

Application filed August 13, 1900. Renewed March 7, 1904. Serial No.196.985.

To all whom it may concern.-

Be it known that I, JOHN MAoDoUeALL, of Detroit, in the county ofI/Vayne, and in the State of Michigan, have invented certain new anduseful Improvements in Filters; and

I do hereby declare that the following is a full, clear, and exactdescription thereof, .reference being had to the accompanying drawings,in which Figure 1 is a top plan view of a filter em bodying myinvention, parts above the filter-bed agitator being omitted for thesake of clearness. Fig. 2 is a vertical section through the same, andFig. 3 is a detail perspective view of a portion of the filter-bedsupport.

Letters of like name and kind refer to like parts in each of thefigures.

The object of my invention is to provide a water-filter of thegranular-bed type having a strong and durable tank capable of cheapconstruction, a simple, eflicient, and convenient form of support forthe filter-bed, and means for efficient and economical cleaning of thebed; and to these ends said invention consists in the filter having thefeatures of construction substantially as hereinafter specified.

In the carrying of my invention into pracice a suitable tank orreceptacle A is employed, into which runs an inletpipc B, by which waterto be filtered is conducted to it, and having an outlet-pipe C forfiltered water. The tank has metallic sides or walls, and riveted to itaround its lower end or bottom is a ring of angle-iron a, that forms asupport or base and stiffens it. It rests on a bed or foundation,preferably of concrete, and within it and resting on the bed is a bottoma of concrete or the like, the surface of which is coated with asphaltor tar and the joint between it and the walls made tight by a filling aof the same material. Thus constructed the tank is cheap, strong,durable, and efficient, and while I therefore prefer it it is to beunderstood that as far as other features of my filter to be describedare con cerned tanks of different construction may be employed. Withinthe tank A and resting on a false bottom or support is a bed offiltering material formed, preferably, of a top layer D of fine sand, asecond layer E of coarse sand, and a third layer F of broken stone,which rests directly on the false bottom.

The false bottom is composed of one or more layers G and G of woven wireor other foraminous material, resting upon a grid composed of numerousposts H and II, secured to the tank-bottom, and thin bars I and I, thatare supported by the posts. The upper ends of the posts are providedwith vertical slots or notches h and h, in which the ends of the bars Iand I are placed. The len th of each of the bars is preferably such thatit reaches from one post to the one nearest it, and the bars are notfastened to the posts, but merely rest freely in the notches therein, sothat they may be readily removed and replaced. Between the posts nearestthe side walls of the tank bars K and K are placed, whose ends next thewall rest on flanges L and. L thereon. Should there for any reason beoccasion to have access to any particular portion of the water-space inthe tank below the filter-bed, such access can be had without disturbingthe entire filter-bed and grid,

it being necessary simply to remove the filterbed at the desired pointand to take out the bars thereat.

At the center of the tank is a vertical shaft M, that at its lower endcarries one or more (as shown, two) arms or paddles N and N, from whoselower edges project teeth a and a, that extend into the upper part ofthe filterbed. The teeth a of one paddle are preferably located so as tocome opposite the space between the teeth of the other paddle to causethe two sets of teeth to traverse different paths, and so insure in morethorough and complete agitation of the sand during the process ofwashing than would be the case were both sets of teeth to traverse thesame paths. The shaft rests at its lower end upon the upper end of apost 0, that rises from the tank-bottom, the upper end of the post beingconical and the shaft having a correspondingly-shaped cavity to fit saidpost end. Intermediate its ends the shaft is supported a ainst pressurein a vertical direction by a thrust-bearing P upon a beam Q, thatextends diametrically across the tank and is b'olted at its ends to thesides thereof, and at its upper end the shaft is journaled in a bearingR upon a cross-beam S, that rests at its ends on the top of the tank.Above the bearing R the shaft carries a suitablydriven bevel gear-wheelT, which has a hub or collar that rests on the top of the bearing It,and the shaft is thereby additionally supported or sustained againstdownward movement.

For the outlet of wash-water from the tank the side walls of the latterhave one or more, preferably several, openings U and U, from which,respectively, pipes V and V, each having a valve a), run to a sewer orother place of discharge. The Openings U and U are placed just above thetop of the filter-bed and in line horizontally with the paddles, and asthe latter by their revolution throw the water in a centrifugaldirection its dis charge through said openings can be quickly effected.As it is undesirable to permit the water to have a circular motion inthe tank, because of the possibility that its momentum may besu'liicient to cause its passage by the outlets, means are provided tobreak up or prevent such motion and assist in the expulsion of the waterthrough the outlets. As shown, the means for this purpose consists ofone or more, preferably two, plates IN and W, that are attached at oneof their ends to the side wall of the tank and project inwardlytherefrom, so as to be in the path of the water in its circular motionin the tank. As the plates are therefore in the path of the paddles, theconstruction employed is such that when engaged by the paddles they willyield before them and move out of their way. To enable them to do this,they may, as shown, be sufficiently flexible or elastic to yield underthe pressure of the paddles, but stiff enough to oppose and change thedirection of the water. That the paddles may most readily and easilythrust the plates aside and the better perform their function ofimparting centrifugal movement to the water their advancing or forwardsides are curved conveXly, as shown. Byreason of this curvature theirgeneral direction is such that they incline rearward from a plane radialto the shaft. Because of this'rearward inclination their action inforcing the water outward or centrifugally is materially enhanced. As itis desirable to arrest the circular motion of the waters in filtershaving differently-located wash-water outlets, it is to be understoodthat, broadly considered, this feature of my invention is not to berestricted to the location or kind of washwater outlet used.

When the filter-bed is to be cleaned, the valve of the inlet-pipe B isclosed and the valve of the outlet-pipe C is kept open until the levelof the water in the filter is lowered to a point where the paddles are alittle more than submerged, and when this level is reached theoutlet-pipe valve is closed. The paddles are now revolved to agitate theupper part of the filter-bed to loosen up and dislodge the accumulatedmatters. thereon and to cause their commingling and suspension in thebody of water left in the filter above the bed, and when this treatmenthas been arried to the desired degree, as evidenced by the condition ofthe water, the valves in the outlet-pipes are opened and the befouled ordirty Water rapidly carried ofi therethrough by reason of the combinedaction of the paddles and the obstructing devices or plates. To completethe washing, filtered water, by pumping or otherwise, is forced throughthe effluent-pipe C or a pipe provided for thepurose back into thefilter at such a rate as not to disturb the bed, but suflicient to carrysuch sediment as may yet be present out of the same, where, with thewater, it may be carried off throughthe wash-water outlets. During thelast-described part of the operation the revolution of the paddles iscontinued, but preferably at a slower rate, and at no time is therevolution so rapid as to result in the carrying off of any of the sandwith the water.

Though preferring to employ all of the features of construction shownand described in a single filter, it is evident that some only may beused in a particular filter and that changes in details of constructionin many respects may be resorted to which will in volve no change in theprinciple of the invention.

Having thus described my invention, what I claim is 1. In a filter, thecombination of a tank having a wash-water outlet, means for impartingcentrifugal motion to the water, and means for arresting circular motionof the water, substantially as and for the purpose described.

2. In a filter, the combination of a tank having a lateral wash-wateroutlet, means for imparting centrifugal motion to the water, and meansfor arresting circular motion of the water, substantially as and for thepurpose described.

3. In a filter, the combinationof 'a tank having a wash-water outlet,rotary paddles, and means for arresting circular motion of the Water,substantially as and for the purpose described.

4. In a filter, the combination of a tank having a wash-water outlet,rotary paddles, and one or more yielding water obstructions,substantially as and for the purpose described.

5. In a filter, the combination of a tank having a wash-water outlet, agranular filterbed, rotary paddles carrying teeth, and means forarresting circular motion of the water, substantially as and for thepurpose described.

In testimony that I claim the foregoing I have hereunto set my hand this30th day of July, A. D. 1900.

JOHN MAoDOUGALL. I/Vit'nesses:

A. J. MAODOUGALL, WM. G. CLARK.

IIO

